March brings college basketball madness, buds of spring and the Ides, that big day in Roman history. But will the month also yield the next Republican presidential nominee?

It’s been the case for half the non-incumbent GOP standard bearers since Ronald Reagan, and Donald Trump’s lock on things this year seemed to be getting even tighter after the month began with big state wins on Super Tuesday.

Although his campaign gained enormous momentum, he’s not a runaway yet — and precedent, it seems this season, is as reliable for gauging outcomes as the weather in March. So the winds will keep blowing.

As of Sunday, Trump was about 857 delegates short of the 1,237 needed to clinch the nomination. Even if the New York real estate mogul wins all the delegates awarded through the rest of this month — which is basically impossible — he won’t come out atop the ticket.

In fact, Trump can’t mathematically lock up the nomination until April 19, even if he wins every delegate in every state beginning Tuesday, when Michigan, Hawaii, Idaho and Mississippi will decide.

Though momentum and the element of time matter in campaigns, the schedule of awarding delegates — known as the primary calendar — changes from year to year.

In 2008, for example, John McCain had a seemingly early primary victory on March 4. But because of that year’s schedule, he had actually gone through 39 primary and caucus states, more than any candidate in the modern primary era up to that point.

In the 2000s, states seeking more influence in the primary process moved their contests earlier into the year, which resulted in a “front-loading” peak in 2000 and 2008, said Josh Putnam, a political science lecturer at the University of Georgia who runs the primary-focused Frontloading HQ blog .

“That has a tendency to advantage the candidates that have the most money and name recognition coming into primary season,” Putnam said.

This year, the primary calendar had no contests in January and fewer in February than in recent elections. So although Super Tuesday might have seemed like a big start to the month, fewer states have voted at this point than in 2008 and 2012.

Going back further, George W. Bush in 2000 and Bob Dole in 1996 won their nominations in March. But unlike McCain, they did it quickly in their primary calendars. Bush did it after 30 states voted, and Dole had to compete through only 27 of the 43 states in the 1996 primary process.

George H.W. Bush clinched his nomination in April 1988, and Ronald Reagan took until May in 1980. Romney went through May in 2012, beating McCain’s previous record and going through 43 states before wrapping up his victory.
So don’t let March’s 32 contests, with a combined 1,434 delegates up for grabs, fool you.

Trump is still the front-runner, but he’s got more work to do. And no one can claim the prize until the full flower of April — at the earliest.